PLA-TC was synthesized firstly according to our previous work [41]. Then, PLA-TC (150 mg) was mixed with AIBN (0.18 mg), tertbutyl acrylate (tBA 50 μl) and 1,4-dioxane (1.5 ml) in a reaction vessel and degassed by 3 freeze–pump–thaw cycles. The reaction was then conducted at 50 °C for 15 h. The resulting reaction mixture was then precipitated from THF to the solution methanol/water (1:2) 3 times and dried under vacuum at 25 °C for 24 h. Yield = 160 mg. GPC (PS standards): Mn =18 kg/mol, Mw/Mn = 1.32. 1 H NMR: n (tBA) = 11.